[fix][mpfa][fvgridgeom] rearrange public aliases

clang3.8 threw a compiler error because it couldn't extract the
types from the fv grid geometry within the helper class. Putting
the helper after the other types (that are tried to be extracted
within the helper) solved this issue.

dumux/discretization/cellcentered/mpfa/fvgridgeometry.hh

@@ -85,14 +85,10 @@ class CCMpfaFVGridGeometry<GV, Traits, true>
     using ScvfOutsideGridIndexStorage = typename Traits::SubControlVolumeFace::Traits::OutsideGridIndexStorage;
 
     // check if two types of interaction volumes are considered in this problem
-    using Helper = typename Traits::template MpfaHelper<ThisType>;
-    static constexpr bool considerSecondaryIVs = Helper::considerSecondaryIVs();
 
 public:
     //! export the flip scvf index set type
     using FlipScvfIndexSet = std::vector<ScvfOutsideGridIndexStorage>;
-    //! export the mpfa helper type
-    using MpfaHelper = Helper;
     //! export the grid interaction volume index set type
     using GridIVIndexSets = typename Traits::template GridIvIndexSets<ThisType>;
     //! export the type to be used for indicators where to use the secondary ivs
@@ -110,6 +106,8 @@ public:
     using DofMapper = typename Traits::ElementMapper;
     //! export the grid view type
     using GridView = GV;
+    //! export the mpfa helper type
+    using MpfaHelper = typename Traits::template MpfaHelper<ThisType>;
 
     //! export the discretization method this geometry belongs to
     static constexpr DiscretizationMethod discMethod = DiscretizationMethod::ccmpfa;
@@ -117,6 +115,9 @@ public:
     //! The maximum admissible stencil size (used for static memory allocation during assembly)
     static constexpr int maxElementStencilSize = Traits::maxElementStencilSize;
 
+    //! State if only a single type is used for interaction volumes
+    static constexpr bool hasSingleInteractionVolumeType = !MpfaHelper::considerSecondaryIVs();
+
     //! Constructor without indicator function for secondary interaction volumes
     //! Per default, we use the secondary IVs at branching points & boundaries
     CCMpfaFVGridGeometry(const GridView& gridView)
@@ -158,13 +159,13 @@ public:
 
     //! Returns true if secondary interaction volumes are used around a given vertex (index).
     //! This specialization is enabled if the use of secondary interaction volumes is active.
-    template<bool useSecondary = considerSecondaryIVs, std::enable_if_t<useSecondary, bool> = 0>
+    template<bool useSecondary = !hasSingleInteractionVolumeType, std::enable_if_t<useSecondary, bool> = 0>
     bool vertexUsesSecondaryInteractionVolume(GridIndexType vIdxGlobal) const
     { return secondaryInteractionVolumeVertices_[vIdxGlobal]; }
 
     //! Returns true if secondary interaction volumes are used around a given vertex (index).
     //! If the use of secondary interaction volumes is disabled, this can be evaluated at compile time.
-    template<bool useSecondary = considerSecondaryIVs, std::enable_if_t<!useSecondary, bool> = 0>
+    template<bool useSecondary = !hasSingleInteractionVolumeType, std::enable_if_t<!useSecondary, bool> = 0>
     constexpr bool vertexUsesSecondaryInteractionVolume(GridIndexType vIdxGlobal) const { return false; }
 
     //! update all fvElementGeometries (do this again after grid adaption)
@@ -443,15 +444,9 @@ class CCMpfaFVGridGeometry<GV, Traits, false>
 
     using ScvfOutsideGridIndexStorage = typename Traits::SubControlVolumeFace::Traits::OutsideGridIndexStorage;
 
-    // check if two types of interaction volumes are considered in this problem
-    using Helper = typename Traits::template MpfaHelper<ThisType>;
-    static constexpr bool considerSecondaryIVs = Helper::considerSecondaryIVs();
-
 public:
     //! export the flip scvf index set type
     using FlipScvfIndexSet = std::vector<ScvfOutsideGridIndexStorage>;
-    //! export the mpfa helper type
-    using MpfaHelper = Helper;
     //! export the grid interaction volume index set type
     using GridIVIndexSets = typename Traits::template GridIvIndexSets<ThisType>;
     //! export the type to be used for indicators where to use the secondary ivs
@@ -469,6 +464,8 @@ public:
     using DofMapper = typename Traits::ElementMapper;
     //! export the grid view type
     using GridView = GV;
+    //! export the mpfa helper type
+    using MpfaHelper = typename Traits::template MpfaHelper<ThisType>;
 
     //! export the discretization method this geometry belongs to
     static constexpr DiscretizationMethod discMethod = DiscretizationMethod::ccmpfa;
@@ -476,6 +473,9 @@ public:
     //! The maximum admissible stencil size (used for static memory allocation during assembly)
     static constexpr int maxElementStencilSize = Traits::maxElementStencilSize;
 
+    //! State if only a single type is used for interaction volumes
+    static constexpr bool hasSingleInteractionVolumeType = !MpfaHelper::considerSecondaryIVs();
+
     //! Constructor without indicator function for secondary interaction volumes
     //! Per default, we use the secondary IVs at branching points & boundaries
     CCMpfaFVGridGeometry(const GridView& gridView)
@@ -517,13 +517,13 @@ public:
 
     //! Returns true if secondary interaction volumes are used around a given vertex (index).
     //! This specialization is enabled if the use of secondary interaction volumes is active.
-    template<bool useSecondary = considerSecondaryIVs, std::enable_if_t<useSecondary, bool> = 0>
+    template<bool useSecondary = !hasSingleInteractionVolumeType, std::enable_if_t<useSecondary, bool> = 0>
     bool vertexUsesSecondaryInteractionVolume(GridIndexType vIdxGlobal) const
     { return secondaryInteractionVolumeVertices_[vIdxGlobal]; }
 
     //! Returns true if secondary interaction volumes are used around a given vertex (index).
     //! If the use of secondary interaction volumes is disabled, this can be evaluated at compile time.
-    template<bool useSecondary = considerSecondaryIVs, std::enable_if_t<!useSecondary, bool> = 0>
+    template<bool useSecondary = !hasSingleInteractionVolumeType, std::enable_if_t<!useSecondary, bool> = 0>
     constexpr bool vertexUsesSecondaryInteractionVolume(GridIndexType vIdxGlobal) const { return false; }
 
     //! Returns true if a given vertex lies on a processor boundary inside a ghost element.